Name: novel apparatus and method for drug reinforcement
Uploaded: 2010-08-20T17:00:00
Duration: 7 min 32 s
Description: Watch this Scientific Journal Video about Novel Apparatus and Method for Drug Reinforcement at JoVE.com

We would like to thank Leah McAleer for her support in conducting this experiment and her help in the poster presentation at the 2009 Society for Neuroscience Meeting and this video production, along with Mohamed Abdalla and Allison Ahrens. We also appreciate Rosie Maddox, Rachel Chavana, and Linda Ju for their assistance in data collection and analyses for this experiment. This project was supported by NIH/NIDA Grant 3R01DA014640-05S1 (C.L.D), The Waggoner Center for Alcohol and Addiction Research Jones Fellowship and NIH/NIAA Training Grant AA07471 (A.A.F). Cocaine HCl was generously supplied by the NIDA Drug Inventory and Supply and Control Program.

*=most important steps
<ol>
	<li>Well-handled male Sprague-Dawley rats are trained to lever press with food reward (45 mg sucrose pellets; Bio-Serv, Frenchtown, NJ).</li>
	<li>*Intravenous catheters are constructed out of stainless steel cannula (Plastics One, VA) and Silastic tubing. Rats undergo a jugular catheterization surgical procedure to allow drug self-administration. Anesthesia consisted of a mixture of oxygen (0.8 l/min; Airgas Southwest, Corpus Christi, TX) and isoflurane (2.5-4%; AErrane, Baxter Healthcare, Deerfield, IL) delivered via a gas delivery system (VetEquip, Inc, Pleasanton, CA). After surgery, catheter patency is maintained by daily flushing with 0.1 ml of a 0.9% saline, heparin and Timentin (antibiotic) solution. Gentamicin, a topical antibiotic, is applied to the skull cap and chest incision to prevent infection. All surgical procedures followed the guidelines for sterile animal surgeries. Surgery supplies were autoclaved and instruments were sterilized in a chemical solution and hot bead sterilizer. Implanted catheters were flushed with methanol, water and air during preparation and then bathed in 70% ethanol solution on the day of surgery. Rats were prepared for surgery by shaving the head and chest area followed application of a betadine solution. After surgery, rats were monitored for several hours before beginning returned to the animal colony.</li>
	<li>Cocaine (NIDA Drug Inventory and Supply and Control Program; RTI International, Research Triangle Park, NC) used in this experiment was dissolved in isotonic saline solution (0.9%) in the appropriate dose concentrations according to animal weights. Cocaine solutions were then filtered through 0.2 um sterile syringe filters prior to daily use.</li>
	<li>*The apparatus is constructed out of two single-lever operant chambers (28 x 22 x 21 cm) equipped with house and stimulus lights and 3 sets of photobeams (Med Associates, St. Albans, VT). Chambers are joined together by a constructed Plexiglas alley (21 x 25 x 25 cm). The alley consists of two black walls with white stripes and two metal walls, a clear Plexiglas top, and a white Plexiglas floor. The two operant chambers have steel grid rod (4.8 mm) floors installed over removable metal cage bottoms. Sensory cues are placed within the operant chambers to create unique, distinguishable environments. The visual cues consist of either white or black felt material attached to the front and back walls and over the cage top. The olfactory cues are oil-based scents (rose or cinnamon) saturating a cotton ball located under the rod floor of the chamber.</li>
	<li>The experimental procedure occurs over multiple days, starting with baseline preference tests (2 days), followed by drug self-administration sessions (8 or 16 days), and ending with a conditioned place preference (CPP) test (1 day).</li>
	<li>*During baseline preference and CPP test procedures, animals have access to both operant chambers. A video camera mounted above the apparatus records the rats' entrances and exits for each chamber. Photobeams within the chambers detect beam breakages that are used as an index of locomotor activity. During drug self-administration sessions, animals are restricted to a single operant chamber while lever response and locomotor activity (e.g., photobeam breakages) data are recorded with a Med Pentium 100 MHZ computer equipped with Med-PC software (Med Associates, Inc., St. Albans, Vermont).</li>
	<li>Baseline preference measurements are collected on two consecutive days. To begin, the rat is placed in the center alley with access to both operant chambers for a 20-min period. Immediately after placement in the chamber, the video camera, Med-PC software program and timer are simultaneously activated. The baseline preference data are assessed during viewings of the video recordings.</li>
	<li>*Drug self-administration sessions commence the day after the last baseline test. Sensory cues (e.g., white or black wall coverings and rose or cinnamon scents) and a panel to block off access to the Plexiglas center alley are placed into the chamber before the animal. To start the session, the animal is placed within the chamber while tubing from the mounted drug syringe is attached to the animal's catheter inlet. After closing the operant chamber door, the Med-PC program and timer is started and cocaine access is available for 1 hour. Each lever response results in the infusion of 0.1 ml of cocaine (0.75 mg/kg/inj) or saline solution. At the end of each self-administration session the rat is disconnected from the drug tubing, removed from the chamber and placed in the home cage.</li>
	<li>The day after the last self-administration session, animals undergo a conditioned place preference (CPP) test. The procedure is the same as described for baseline measurements (see 7).</li>
	<li>*Data Assessment: An experimenter blind to group assignments determines the amount of time the animals spend in each compartment by viewing the videotape to assess entrances and exits between the compartments for a 15-min period (beginning 5 min after placement within the apparatus). The same procedure is used to determine baseline preference and CPP test scores.</li>
	<li>*Data Analyses: Differences between baseline measurements and post-conditioning CPP scores are used to determine drug-conditioning effects. Difference scores are calculated by subtracting the amount of time spent in the saline-paired compartment from the amount of time spent in the drug-paired compartment during the CPP test (Number of seconds in Drug-paired compartment) - (Number of seconds in Saline-paired compartment). Statistical analyses on difference score changes from Baseline to Test sessions can be performed to determine effects of drug conditioning.</li>
</ol>
CPP scores can also be expressed as CPP Difference Scores Percentage (%). In the present study, CPP Difference Score % was calculated first by determining the percent of time spent in each operant chamber using the formula: (Time in Drug (OR Saline) Chamber/Total Time in Each Chamber) * 100 = % Conditioned Place Preference (CPP). The difference score percentage was determined by the formula: (Drug-paired %) - (Saline-paired %) = CPP Difference Score %.
<img src="/files/ftp_upload/1998/1998fig1.jpg" alt="Figure 1" /> Figure 1. Relationship between Cocaine Intake and Conditioned Place Preference. Pearson's Correlation analyses determined a significant positive correlation between Total Cocaine-Reinforced Lever Responses and CPP Difference Score % for animals that had self-administered cocaine for eight sessions (e.g., the Long-term group; p &lt; 0.05), but not for animals in the Short-term group (e.g., 4 cocaine sessions). Open diamonds represent individual data points for the Cocaine Long-term (n=9) and filled circles represent the Cocaine Short-term (n= 8) groups. Best-fit lines are dashed for Long-term, and solid for Short-term data points.

<ol>
	<li>Sanchis-Segura, C., Spanagel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioural+assessment+of+drug+reinforcement+and+addictive+features+in+rodents:+an+overview.">Behavioural assessment of drug reinforcement and addictive features in rodents: an overview.</a> Addict Biol. 11 (1), 2-2 (2006).</li><li>Tzschentke, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+reward+with+the+conditioned+place+preference+(CPP)+paradigm:+update+of+the+last+decade.">Measuring reward with the conditioned place preference (CPP) paradigm: update of the last decade.</a> Addict Biol. 12 (3-4), 227-227 (2007).</li><li>Koob, G. F., Bloom, K. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Psychopharmacology: the fourth generation of progress. , 759-759 (1995).</li><li>Bardo, M. T., Bevins, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Conditioned+place+preference:+what+does+it+add+to+our+preclinical+understanding+of+drug+reward.">Conditioned place preference: what does it add to our preclinical understanding of drug reward.</a> Psychopharmacology (Berl). 153 (1), 31-31 (2000).</li><li>Panlilio, L. V., Goldberg, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-administration+of+drugs+in+animals+and+humans+as+a+model+and+an+investigative+tool.">Self-administration of drugs in animals and humans as a model and an investigative tool.</a> Addiction. 102 (12), 1863-1863 (2007).</li><li>Stefanski, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Active+versus+passive+cocaine+administration:+differences+in+the+neuroadaptive+changes+in+the+brain+dopaminergic+system.">Active versus passive cocaine administration: differences in the neuroadaptive changes in the brain dopaminergic system.</a> Brain Res. 1157, 1-1 (2007).</li><li>Miguens, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+cocaine-induced+modulation+of+glutamate+and+dopamine+transporters+after+contingent+and+non-contingent+administration.">Differential cocaine-induced modulation of glutamate and dopamine transporters after contingent and non-contingent administration.</a> Neuropharmacology. 55 (5), 771-771 (2008).</li><li>Palamarchouk, V., Smagin, G., Goeders, N. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-administered+and+passive+cocaine+infusions+produce+different+effects+on+corticosterone+concentrations+in+the+medial+prefrontal+cortex+(MPC)+of+rats.">Self-administered and passive cocaine infusions produce different effects on corticosterone concentrations in the medial prefrontal cortex (MPC) of rats.</a> Pharmacol Biochem Behav. 94 (1), 163-163 (2009).</li><li>Ciano, P. D. i., Blaha, C. D., Phillips, A. 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The video production of this article was sponsored by Med Associate, which produces instruments used in this article.

Operant intravenous drug self-administration and place conditioning procedures are reliable and valid models for studying the neurobiological bases for drug dependence and addiction 1 2 3. Both methods are widely used in pre-clinical drug abuse research and are able to measure the reinforcing properties of abused drugs 4. However, both methods have shortcomings that the new apparatus and method presented here improves upon 5.
One large drawback of traditional CPP procedures is the non-contingent mode of drug administration. This mode of drug intake has different behavioral and neurochemical outcomes than self-administration 6 7 8 9 10 11 , and is not consistent with human drug-taking experiences. Additionally, unlike drug self-administration procedures, CPP paradigms are unable to measure progressive changes in drug motivation as reflected by increased drug intake; a putative turning point in the switch from recreational drug use to uncontrollable drug addiction. However, drug self-administration behavior has interpretive limitations as well. For instance, response rates are often used to infer reward value, but can be directly influenced by motoric effects of the self-administered drug, independent of the drug's motivational effects. In addition, the number of drug-reinforced responses can also be influenced by presence or absence of drug infusion-associated stimuli 12.
Cocaine is known to be readily self-administered by rats and produce robust conditioned place preferences at a variety of doses and routes of administration 2 13 14. The results from the present study support previous reports of drug reinforcement models. In addition, a significant positive relationship between cocaine-reinforced lever responses and CPP scores was determined in the Long-, but not the Short-term Cocaine group. These results suggest that place conditioning and self-administration are not necessarily isomorphic measures of reward. For instance, it is conceivable that CPP after short-term cocaine exposure reflects acute reinforcing properties typically seen with initial recreational drug use. On the other hand, in rats with more cocaine experience, cocaine intake escalation in correspondence with increasing levels of conditioned reinforcement may indicate progressive changes in drug sensitivity or enhanced rewarding drug effects in certain populations. 
This featured method has utility beyond assessing the positive reinforcing effects of drugs. For instance, aversive effects of drugs not present during initial drug use can emerge with extended drug exposure (e.g., conditioned place aversions, or CPA) and would be detectable using this technique. Additional uses include the potential to screen for subpopulations most sensitive to cocaine-cue associative learning, to assess experience-mediated changes in cocaine-motivated behaviors, and to detect enduring drug-conditioned effects during drug abstinence and/or cued reinstatement. In conclusion, this apparatus and approach is time and cost effective, can be used to examine a wide array of topics pertaining to drug abuse, and provides more flexibility in experimental design than CPP or self-administration methods alone.

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		<th>Type</th>
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		<th>Catalogue Number</th>
		<th>Comment</th>
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<tr>
<td>Operant Conditioning Behavior (Drug Self-administration) Test Package for Rat</td>
<td>&nbsp;</td>
<td><a href="http://www.med-associates.com/">Med Associates, Inc</a></td>
<td>MED-008-CT-B1</td>
<td>&nbsp;</td>
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<td>Infrared Source and Detector (Photobeams)</td>
<td>&nbsp;</td>
<td><a href="http://www.med-associates.com/">Med Associates, Inc</a></td>
<td>ENV-253SD ENV-253</td>
<td>&nbsp;</td>
<tr>
<td>Med PC Software</td>
<td>&nbsp;</td>
<td><a href="http://www.med-associates.com/">Med Associates, Inc</a></td>
<td>SOF-735</td>
<td>&nbsp;</td>
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<td>Single speed syringe pump</td>
<td>&nbsp;</td>
<td>Razel Scientific Instruments</td>
<td>Model R-E</td>
<td>&nbsp;</td>
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<td>45 mg sucrose pellets</td>
<td>&nbsp;</td>
<td>Bio-Serv</td>
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<td>Catheter cannula</td>
<td>&nbsp;</td>
<td>Plastics One</td>
<td>C313G-5UP</td>
<td>&nbsp;</td>
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<td>Cocaine</td>
<td>&nbsp;</td>
<td>RTI International</td>
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novel apparatus and method for drug reinforcement

Animal models of reinforcement have proven to be useful for understanding the neurobiological mechanisms underlying drug addiction. Operant drug self-administration and conditioned place preference (CPP) procedures are expansively used in animal research to model various components of drug reinforcement, consumption, and addiction in humans. For this study, we used a novel approach to studying drug reinforcement in rats by combining traditional CPP and self-administration methodologies. We assembled an apparatus using two Med Associate operant chambers, sensory stimuli, and a Plexiglas-constructed neutral zone. These modifications allowed our experiments to encompass motivational aspects of drug intake through self-administration and drug-free assessment of drug/cue conditioning strength with the CPP test. In our experiments, rats self-administered cocaine (0.75 mg/kg/inj, i.v.) during either four (e.g., the "short-term") or eight (e.g., the "long-term") alternating-day sessions in an operant environment containing distinctive sensory cues (e.g., olfactory and visual). On the alternate days, in the other (differently-cued) operant environment, saline was available for self-infusion (0.1 ml, i.v.). Twenty-four hours after the last self-administration/cue-pairing session, a CPP test was conducted. Consistent with typical CPP findings, there was a significant preference for the chamber associated with cocaine self-administration. In addition, in animals undergoing the long-term experiment, a significant positive correlation between CPP magnitude and the number of cocaine-reinforced lever responses. In conclusion, this apparatus and approach is time and cost effective, can be used to examine a wide array of topics pertaining to drug abuse, and provides more flexibility in experimental design than CPP or self-administration methods alone.

Watch this Scientific Journal Video about Novel Apparatus and Method for Drug Reinforcement at JoVE.com

Novel Apparatus and Method for Drug Reinforcement

Operant drug self-administration and conditioned place preference (CPP) procedures are expansively used in research to model various components of drug reinforcement, consumption, and addiction in humans. In this report, we combined traditional CPP and self-administration methods as a novel approach to studying drug reinforcement and addiction in rats.

Animal models of reinforcement have proven to be useful for understanding the neurobiological mechanisms underlying drug addiction.  Operant drug ...

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A Novel Method for Assessing Proximal and Distal Forelimb Function in the Rat: the Irvine, Beatties and Bresnahan (IBB) Forelimb Scale

Several experimental models of cervical spinal cord injury (SCI) have been developed recently to assess the consequences of damage to this level of the spinal cord (Pearse et al., 2005, Gensel et al., 2006, Anderson et al., 2009), as the majority of human SCI occur here (Young, 2010; www.sci-info-pages.com). Behavioral deficits include loss of forelimb function due to damage to the white matter affecting both descending motor and ascending sensory systems, and to the gray matter containing the segmental circuitry for processing sensory input and motor output for the forelimb. Additionally, a key priority for human patients with cervical SCI is restoration of hand/arm function (Anderson, 2004). Thus, outcome measures that assess both proximal and distal forelimb function are needed. Although there are several behavioral assays that are sensitive to different aspects of forelimb recovery in experimental models of cervical SCI (Girgis et al., 2007, Gensel et al., 2006, Ballerman et al., 2001, Metz and Whishaw, 2000, Bertelli and Mira, 1993, Montoya et al., 1991, Whishaw and Pellis, 1990), few techniques provide detailed information on the recovery of fine motor control and digit movement.
The current measurement technique, the Irvine, Beatties and Bresnahan forelimb scale (IBB), can detect recovery of both proximal and distal forelimb function including digit movements during a naturally occurring behavior that does not require extensive training or deprivation to enhance motivation. The IBB was generated by observing recovery after a unilateral C6 SCI, and involves video recording of animals eating two differently shaped cereals (spherical and doughnut) of a consistent size. These videos were then used to assess features of forelimb use, such as joint position, object support, digit movement and grasping technique.
The IBB, like other forelimb behavioral tasks, shows a consistent pattern of recovery that is sensitive to injury severity. Furthermore, the IBB scale could be used to assess recovery following other types of injury that impact normal forelimb function.

A Novel Method for Assessing Proximal and Distal Forelimb Function in the Rat: the Irvine, Beatties and Bresnahan IBB Forelimb Scale

Here we will describe a rodent behavioral assay that can detect recovery of both proximal and distal forelimb function including digit movements during a naturally occurring behavior that does not require extensive training or deprivation to enhance motivation.

Several experimental models of cervical spinal cord injury (SCI) have been developed recently to assess the consequences of damage to this level of the ...

A Novel Method of Drug Administration to Multiple Zebrafish (Danio rerio) and the Quantification of Withdrawal

Anxiety testing in zebrafish is often studied in combination with the application of pharmacological substances. In these studies, fish are routinely netted and transported between home aquaria and dosing tanks. In order to enhance the ease of compound administration, a novel method for transferring fish between tanks for drug administration was developed. Inserts that are designed for spawning were used to transfer groups of fish into the drug solution, allowing accurate dosing of all fish in the group. This increases the precision and efficiency of dosing, which becomes very important in long schedules of repeated drug administration. We implemented this procedure for use in a study examining the behavior of zebrafish in the light/dark test after administering ethanol with differing 21 day schedules. In fish exposed to daily-moderate amounts of alcohol there was a significant difference in location preference after 2 days of withdrawal when compared to the control group. However, a significant difference in location preference in a group exposed to weekly-binge administration was not observed. 
This protocol can be generalized for use with all types of compounds that are water-soluble and may be used in any situation when the behavior of fish during or after long schedules of drug administration is being examined. The light/dark test is also a valuable method of assessing withdrawal-induced changes in anxiety.

A Novel Method of Drug Administration to Multiple Zebrafish Danio rerio and the Quantification of Withdrawal

A novel method for reducing variability when exposing fish to drugs is explained. Fish exposed to various patterns of ethanol exposure were found to have altered anxiety levels during withdrawal in a light/dark scototaxic assay.

Anxiety testing in zebrafish is often studied in combination with the application of pharmacological substances. In these studies, fish are routinely ...

Assessment of Neuronal Viability Using Fluorescein Diacetate-Propidium Iodide Double Staining in Cerebellar Granule Neuron Culture

Primary cultured Cerebellar Granule Neurons (CGNs) have been widely used as an in vitro model in neuroscience and neuropharmacology research. However, the co-existence of glial cells and neurons in CGN culture might lead to biases in the accurate assessment of neuronal viability. Fluorescein diacetate (FDA) and Propidium Iodide (PI) double staining has been used to measure cell viability by simultaneously evaluating the viable and dead cells. We used FDA-PI double staining to improve the sensitivities of the colorimetric assays and to evaluate neuronal viability in CGNs. Furthermore, we added blue fluorescent DNA stains (e.g., Hoechst) to improve the accuracy. This protocol describes how to improve the accuracy of assessment of neuronal viability by using these methods in CGN culture. Using this protocol, the number of glial cells can be excluded by using fluorescence microscopy. A similar strategy can be applied to distinguish the unwanted glial cells from neurons in various mixed cell cultures, such as primary cortical culture and hippocampal culture.

This protocol describes how to accurately measure neuronal viability using Fluorescein diacetate (FDA) and Propidium Iodide (PI) double staining in cultured cerebellar granule neurons, a primary neuronal culture used as an in vitro model in neuroscience and neuropharmacology research.

Primary cultured Cerebellar Granule Neurons (CGNs) have been widely used as an in vitro model in neuroscience and neuropharmacology research. However, the ...

Recording EEG in Freely Moving Neonatal Rats Using a Novel Method

EEG is a useful method to detect electrical activity in the brain. Moreover, it is a widely used diagnostic tool for various neurological conditions, such as epilepsy and neurodegenerative disorders. However, it is technically difficult to obtain EEG recordings in neonates as it requires specialized handling and great care. Here, we present a novel method to record EEG in neonatal rat pups (P8-P15). We designed a simple and reliable electrode using computer pin loci; it can be easily implanted into the skull of a rat pup to record high-quality EEG signals in the normal and epileptic brain. Pups were given an intraperitoneal (i.p.) injection of the neurotoxin kainic acid (KA) to induce epileptic seizures. The surgical implantation performed in this procedure is less expensive than other EEG procedures for neonates. This method allows one to record high-quality and stable EEG signals for more than 1 week. Furthermore, this procedure can also be applied to adult rats and mice to study epilepsy or other neurological disorders.

Here, we introduce a novel technique designed to record electroencephalography (EEG) in freely moving neonatal epileptic pups and describe its procedures, features, and applications. This method allows one to record EEG for more than 1 week.

EEG is a useful method to detect electrical activity in the brain. Moreover, it is a widely used diagnostic tool for various neurological conditions, such ...

Novel Assay for Cold Nociception in Drosophila Larvae

How organisms sense and respond to noxious temperatures is still poorly understood. Further, the mechanisms underlying sensitization of the sensory machinery, such as in patients experiencing peripheral neuropathy or injury-induced sensitization, are not well characterized. The genetically tractable Drosophila model has been used to study the cells and genes required for noxious heat detection, which has yielded multiple conserved genes of interest. Little is known however about the cells and receptors important for noxious cold sensing. Although, Drosophila does not survive prolonged exposure to cold temperatures (&#8804;10 &#186;C), and will avoid cool, preferring warmer temperatures in behavioral preference assays, how they sense and possibly avoid noxious cold stimuli has only recently been investigated.
Here we describe and characterize the first noxious cold (&#8804;10 &#186;C) behavioral assay in Drosophila. Using this tool and assay, we show an investigator how to qualitatively and quantitatively assess cold nociceptive behaviors. This can be done under normal/healthy culture conditions, or presumably in the context of disease, injury or sensitization. Further, this assay can be applied to larvae selected for desired genotypes, which might impact thermosensation, pain, or nociceptive sensitization. Given that pain is a highly conserved process, using this assay to further study&#160;thermal nociception will likely glean important understanding of pain processes in other species, including vertebrates.

Novel Assay for Cold Nociception in Drosophila Larvae

Here we demonstrate a novel assay to study cold nociception in Drosophila larvae. This assay utilizes a custom-built Peltier probe capable of applying a focal noxious cold stimulus and results in quantifiable cold-specific behaviors. This technique will allow further cellular and molecular dissection of cold nociception.

How organisms sense and respond to noxious temperatures is still poorly understood. Further, the mechanisms underlying sensitization of the sensory ...

A Novel Method to Model Chronic Traumatic Encephalopathy in Drosophila

Chronic Traumatic Encephalopathy (CTE) is an established neurodegenerative disease that is closely associated with exposure to repetitive mild Traumatic Brain Injury (mTBI). The mechanisms responsible for its complex pathological changes remain largely elusive, despite a recent consensus to define the neuropathological criteria. Here, we describe a novel method to develop a model of CTE in Drosophila melanogaster&#160;(Drosophila&#160;)&#160;in an attempt to identify the key genes and pathways that lead to the characteristic hyperphosphorylated tau accumulation and neuronal death in the brain. Adjustable-strength impacts to inflict mild closed injury are delivered directly to the fly head, subjecting the head to rapid acceleration and deceleration. Our method eliminates the potential problems inherent with other Drosophila mTBI models (e.g.,animal death might be induced by damage to other parts of the body or to internal organs). The less labor- and cost-intensive animal care, short life span, and extensive genetic tools make the fruit fly ideal to study CTE pathogenesis and make it possible to perform large-scale, genome-wide forward genetic and pharmacological screens. We anticipate that the ongoing characterization of the model will generate important mechanistic insights on disease prevention and therapeutic approaches.

A Novel Method to Model Chronic Traumatic Encephalopathy in Drosophila

Here, we describe a new approach to inflict closed-head traumatic brain injury in Drosophila melanogaster. Our method has the advantage of directly delivering repetitive impacts with adjustable strength to the head alone. Further exploration of the invertebrate system will help to illuminate the pathogenesis of chronic traumatic encephalopathy.

Chronic Traumatic Encephalopathy (CTE) is an established neurodegenerative disease that is closely associated with exposure to repetitive mild Traumatic ...

Assay Development for High Content Quantification of Sod1 Mutant Protein Aggregate Formation in Living Cells

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that can be caused by inherited mutations in the gene encoding copper-zinc superoxide dismutase 1 (SOD1). The structural instability of SOD1 and the detection of SOD1-positive inclusions in familial-ALS patients supports a potential causal role for misfolded and/or aggregated SOD1 in ALS pathology. In this study, we describe the development of a cell-based assay designed to quantify the dynamics of SOD1 aggregation in living cells by high content screening approaches. Using lentiviral vectors, we generated stable cell lines expressing wild-type and mutant A4V SOD1 tagged with yellow fluorescent protein and found that both proteins were expressed in the cytosol without any sign of aggregation. Interestingly, only SOD1 A4V stably expressed in HEK-293, but not in U2OS or SH-SY5Y cell lines, formed aggregates upon proteasome inhibitor treatment. We show that it is possible to quantify aggregation based on dose-response analysis of various proteasome inhibitors, and to track aggregate-formation kinetics by time-lapse microscopy. Our approach introduces the possibility of quantifying the effect of ALS mutations on the role of SOD1 in aggregate formation as well as screening for small molecules that prevent SOD1 A4V aggregation.

We describe a method to quantify the aggregation of misfolded proteins. Our protocol details lentiviral induced stable cell line generation, automated confocal imaging, and image analysis of protein aggregates. As an illustrative application, we studied the effect of small molecules in promoting SOD1 aggregation in a time- and dose-dependent manner.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that can be caused by inherited mutations in the gene encoding copper-zinc ...

Implantation of Chronic Silicon Probes and Recording of Hippocampal Place Cells in an Enriched Treadmill Apparatus

An important requisite for understanding brain function is the identification of behavior and cell activity correlates. Silicon probes are advanced electrodes for large-scale electrophysiological recording of neuronal activity, but the procedures for their chronic implantation are still underdeveloped. The activity of hippocampal place cells is known to correlate with an animal&#39;s position in the environment, but the underlying mechanisms are still unclear. To investigate place cells, here we describe a set of techniques which range from the fabrication of devices for chronic silicon probe implants to the monitoring of place field activity in a cue-enriched treadmill apparatus. A micro-drive and a hat are built by fitting and fastening together 3D-printed plastic parts. A silicon probe is mounted on the micro-drive, cleaned, and coated with dye. A first surgery is performed to fix the hat on the skull of a mouse. Small landmarks are fabricated and attached to the belt of a treadmill. The mouse is trained to run head-fixed on the treadmill. A second surgery is performed to implant the silicon probe in the hippocampus, following which broadband electrophysiological signals are recorded. Finally, the silicon probe is recovered and cleaned for reuse. The analysis of place cell activity in the treadmill reveals a diversity of place field mechanisms, outlining the benefit of the approach.

We describe the diverse steps to implant chronic silicon probes and to record place cells in mice that are running head-fixed on a cue-enriched treadmill apparatus.

An important requisite for understanding brain function is the identification of behavior and cell activity correlates. Silicon probes are advanced ...

CMAP Scan MUNE (MScan) - A Novel Motor Unit Number Estimation (MUNE) Method

Like other methods for motor unit number estimation (MUNE), compound muscle action potential (CMAP) scan MUNE (MScan) is a non-invasive electrophysiologic method to estimate the number of functioning motor units in a muscle. MUNE is an important tool for the assessment of neuropathies and neuronopathies. Unlike most MUNE methods in use, MScan assesses all the motor units in a muscle, by fitting a model to a detailed stimulus-response curve, or CMAP scan. It thereby avoids the bias inherent in all MUNE methods based on extrapolating from a small sample of units. Like &#39;Bayesian MUNE,&#39;&#160;MScan analysis works by fitting a model, made up of motor units with different amplitudes, thresholds, and threshold variabilities, but the fitting method is quite different, and completed within five minutes, rather than several hours. The MScan off-line analysis works in two stages: first, a preliminary model is generated based on the slope and variance of the points in the scan, and second, this model is then refined by adjusting all the parameters to improve the fit between the original scan and scans generated by the model.
This new method has been tested for reproducibility and recording time on 22 amyotrophic lateral sclerosis (ALS) patients and 20 healthy controls, with each test repeated twice by two blinded physicians. MScan showed excellent intra- and inter-rater reproducibility with ICC values of &#62;0.98 and a coefficient of variation averaging 12.3 &#177; 1.6%. There was no difference in the intra-rater reproducibility between the two observers. Average recording time was 6.27 &#177; 0.27 min.
This protocol describes how to record a CMAP scan and how to use the MScan software to derive an estimate of the number and sizes of the functioning motor units. MScan is a fast, convenient, and reproducible method, which may be helpful in diagnoses and monitoring disease progression in neuromuscular disorders.

CMAP Scan MUNE MScan - A Novel Motor Unit Number Estimation MUNE Method

This protocol describes a new method to estimate the number of functioning motor units in a muscle, by fitting a model to a detailed stimulus-response curve of the compound muscle action potential. It is quick and easy to perform and analyze and has excellent reproducibility.

Like other methods for motor unit number estimation (MUNE), compound muscle action potential (CMAP) scan MUNE (MScan) is a non-invasive electrophysiologic ...

Autoradiography as a Simple and Powerful Method for Visualization and Characterization of Pharmacological Targets

In vitro autoradiography aims to visualize the anatomical distribution of a protein of interest in tissue from experimental animals as well as humans. The method is based on the specific binding of a radioligand to its biological target. Therefore, frozen tissue sections are incubated with radioligand solution, and the binding to the target is subsequently localized by the detection of radioactive decay, for example, by using photosensitive film or phosphor imaging plates. Resulting digital autoradiograms display remarkable spatial resolution, which enables quantification and localization of radioligand binding in distinct anatomical structures. Moreover, quantification allows for the pharmacological characterization of ligand affinity by means of dissociation constants (Kd), inhibition constants (Ki) as well as the density of binding sites (Bmax) in selected tissues. Thus, the method provides information about both target localization and ligand selectivity. Here, the technique is exemplified with autoradiographic characterization of the high-affinity &#947;-hydroxybutyric acid (GHB) binding sites in mammalian brain tissue, with special emphasis on methodological considerations regarding the binding assay parameters, the choice of the radioligand and the detection method.

The method of autoradiography is routinely used to study binding of radioligands to tissue sections for determination of qualitative or quantitative pharmacology.

In vitro autoradiography aims to visualize the anatomical distribution of a protein of interest in tissue from experimental animals as well as humans. The ...